Have a 2007 21" imac. friend installed 2, 4GB memory for me, Apple genius says that's what causing slow downs on my machine? when they tested it only had a 4GB & a 2GB cards, so someone along the way did a switch on me. Apple says my machine can only handle 4GB total. i wonder if that's true? seems like it ran quite well for a long time, & it used to corroborate that it had 8 GB memory, so something fishy has occurred. machine is running quirky & would like to have max memory. Would appreciate some knowledgeable input...


Crucial, UK state that 4GB is the maximum amount of RAM that your iMac officially supports.

If you put more in and it worked then this could be seen as a 'bug', and wouldn't be supported by Apple. Such abilities could also be revoked through software/firm was updates.

  • true and not true, mine has max 4gb supported by apple 8gb actual. i upgraded ram around 6 years ago and I've not had any issues and the system makes use of all – Macmaniman Jun 28 '15 at 17:50
  • I’m failing to see what part of what I said could be seen as not true 😕 – forquare Jun 28 '15 at 23:15
  • i meant that the 4gb is not the maximum... which is just what you said. i missed that... my mistake i simply ment that the mac he has apparently supports more than that! – Macmaniman Jun 29 '15 at 0:33

according to Mactracker the mid 2007 imac 20inch has: Maximum Memory 6.0 GB (Actual) 4.0 GB (Apple) Memory Slots 2 - 200-pin PC2-5300 (667MHz) DDR2 SO-DIMM

you should also make sure that you always have the same amount on both slots in your case two 3gb however 3gb rams are rare therefore more expensive

  • Are you saying you have a iMac (20-inch, Mid 2007) with two 4 GB 667 MHz DD2 SDRAM memory modules and OS X reports your total memory is 8 GB? – David Anderson Jun 29 '15 at 0:59
  • no i have a later model, what i am saying is that the max set by apple is not neccerly the real maximum the computer supports. and according to mactracker the 20 inch mid 2007 supports 6gb – Macmaniman Jun 29 '15 at 11:13

In another forum some users have confirmed 2007 iMac works with 8 GB with no issue after the el Captain upgrade.

  • Welcome to Ask Different. We like answers to be more than just a single line. Ideally, you want to explain why your answer is right. It also helps to provide links, citations, and/or screen shots. Please review our help section How to Answer on writing good answers to questions – Allan Jan 18 '17 at 13:54

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .